Alert archive / Louisiana / Mesoscale Discussions in 2011

Mesoscale Discussion 304

March 29, 20114 states

The Storm Prediction Center issued this mesoscale discussion at Mar 29, 2011, 2:48 PM CDT for 4 states. It was in force for 87 min.

The area

The outline as issued.

The facts

Issued: Mar 29, 2011, 2:48 PM CDT (19:48 UTC)
Expired: Mar 29, 2011, 4:15 PM CDT
In force: 87 min
Issued by: the Storm Prediction Center

All 49 counties

Mobile County, AL, Acadia Parish, LA, Allen Parish, LA, Ascension Parish, LA, Assumption Parish, LA, Beauregard Parish, LA, Calcasieu Parish, LA, Cameron Parish, LA, East Baton Rouge Parish, LA, East Feliciana Parish, LA, Evangeline Parish, LA, Iberia Parish, LA, Iberville Parish, LA, Jefferson Davis Parish, LA, Jefferson Parish, LA, Lafayette Parish, LA, Lafourche Parish, LA, Livingston Parish, LA, Orleans Parish, LA, Plaquemines Parish, LA, Pointe Coupee Parish, LA, Saint Bernard Parish, LA, Saint Charles Parish, LA, Saint Helena Parish, LA, Saint James Parish, LA, Saint John the Baptist Parish, LA, Saint Landry Parish, LA, Saint Martin Parish, LA, Saint Tammany Parish, LA, St. Mary Parish, LA, Tangipahoa Parish, LA, Terrebonne Parish, LA, Vermilion Parish, LA, Washington Parish, LA, West Baton Rouge Parish, LA, West Feliciana Parish, LA, Forrest County, MS, George County, MS, Hancock County, MS, Harrison County, MS, Jackson County, MS, Lamar County, MS, Marion County, MS, Pearl River County, MS, Perry County, MS, Pike County, MS, Stone County, MS, Walthall County, MS, Orange County, TX

The watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

Tornado Watch 72Mar 29, 3:20 PM CDT

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 12:00Z, 7.8 hours before the alert went out and 162 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 7 J/kg
Mixed-layer CIN: -508 J/kg
Mixed-layer LCL: 621 m above ground
0-6 km bulk shear: 33 kt
0-1 km storm-relative helicity: 267 m²/s²
0-3 km storm-relative helicity: 248 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 4.4

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <link rel="stylesheet" href="index.css">
</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Mar 29, 3:17 PM CDT	Tornado Watch	SPC	Acadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 34 more	7 hr
Mar 29, 5:26 PM CDT	Mesoscale Discussion	SPC	Bienville, Bossier, Caddo, Caldwell, Claiborne, De Soto and 14 more	2 hr
Mar 29, 6:26 PM CDT	Severe Thunderstorm Watch	SPC	Bienville, Bossier, Caddo, Caldwell, Catahoula, Claiborne and 20 more	8 hr
Mar 29, 6:47 PM CDT	Mesoscale Discussion	SPC	Acadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 33 more	118 min
Mar 29, 2:18 PM CDT	Mesoscale Discussion	SPC	Atascosa, Bandera, Bee, Bexar, DeWitt, Dimmit and 22 more	117 min
Mar 29, 3:57 PM CDT	Severe Thunderstorm Watch	SPC	Aransas, Atascosa, Bandera, Bastrop, Bee, Bexar and 39 more	7 hr
Mar 29, 5:59 PM CDT	Mesoscale Discussion	SPC	Aransas, Atascosa, Bandera, Bastrop, Bee, Bexar and 33 more	2 hr

Nearby

Mesoscale Discussions in Louisiana, 2011 Mesoscale Discussions in Mississippi, 2011 Mesoscale Discussions in Alabama, 2011 Every mesoscale discussion in 2011

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive.